External flue water heater



Feb..8, 1955 R s, RHEEM ETAL 2,701,554

EXTERNAL FLUE WATER HEATER Filed Sept. 11, 1950 5 Sheets-Sheet 2 ICHAPDs. RHEEM a STANTON 1.. mRa/wuaH,

- INVENTORS. HUEB/VER, BEE'HLER, WORREL,

HERZ/G 8 CALDWELL, By ATTORNEYS.

Feb. 8, 1955 s. RHEEM VET AL. 2,701,554

EXTERNAL FLUE WATER HEATER Filed Sept. 11, 1950 5 Shets-Sheet 3 STANTONL. V4 RBROUGH,

IN V EN TORS.

HUEBNER. BEEHLER, WORREL,

HERZ/G 8 CALDWELL ATTORNEYS.

nited States Patent EXTERNAL FLUE WATER HEATER Richard S. Rheem, NewYork, N. Y., and Stanton L. Yarbrough, East Pasadena, Calif., assignorsto Rheem Manufacturing Company, Richmond, Calif., 21 corporation ofCalifornia Application September 11, 1950, Serial No. 184,218

2 Claims. (Cl. 122-19) This invention relates to water heaters and moreparticularly to water heaters of the outside flue type, having a burnerat the bottom of the water tank and a series of fiues spaced around thetank up which the hot gases pass, transferring heat into the water inthe tank.

The principal object of this invention is to improve and simplify theconstruction of such heaters so as to enhance efiiciency and increasedurability for a given cost of construction.

It is a more particular object of this invention to improve the designand configuration of the water tank of an exteral fiue heater so as tosimplify and strengthen its fabrication.

It is another object of this invention to design a heater of the outsideflue type in which special problems in the construction of the watertank are obviated through suitable configuration of the heater.

Other and further objects and advantages will be more apparent from thedrawings and specifications relative thereto.

In prior art heaters of the outside flue type, it has been necessary, inthe past, to design a special fluted end plate for the water tank inorder to accommodate the corrugations in the cylindrical tank. Suchcorrugations, in conjunction with the housing wall of the heater,constituted the external flues. Not only is the fabrication of such anend plate expensive, but adequate sealing of the plate to the tankintroduces complicating problems.

In accordance with the instant invention, fluting of the end plate isobviated by the employment of either one of two alternativeconstructions. In the first type of construction, the water tank is ofconventional cylindrical form and is not deformed, embossed or recessedin any way. The channeling required to create the outside fines iseffected, instead, in the housing of the heater circumjacent the watertank, generally by outwardly deforming or corrugating the inner wall ofthe housing. In the second type of construction, the tank itself isdeformed by being either embossed or recessed, but the deformed portionsdo not extend the full height of the tank. That is to say, they stopshort of the top and bottom edges of the tank, so that a conventionalend plate, generally circular, may be employed, thereby obviating theattendant construction and welding difiiculties inherent in prior artdevices.

By the instant constructionobviating the fluted end plate whichconstitutes the weak point of prior art water tanks-a hotter burner maybe used beneath the water tank. Such a burner, however, causes undueheating of the walls of the burner chamber. This problem is met in theinstant invention by a unique design of inlet passages through whichcombustion air is fed in such a manner that the air serves as aconstantly changing insulation or buffer between the hot burner and thechamber wall.

Several species of the instant invention will now be described inconnection with the accompanying drawings wherein:

Figures 1, 2 and 3 are views of a preferred species of the instantinvention, Figure 1 being a sectional elevation of the heater; Figure 2,a cross-sectional view taken on line 22 of Figure 1; and Figure 3, anenlargement of a portion of the Figure 2 section.

Figures 4 and 5 illustrate the second species of the instant invention,Figure 4 being a sectional elevation and Figure 5, a cross-section takenon line 55 of Figure 4.

Figures 6 and 7 illustrate a third species of the invention, Figure 6being a sectional elevation, and Figure 7 being a cross-section taken online 77 of Figure 6. The embodiment illustrated in Figure 6 bears amarked similarity to that of Figure 4 and may therefore be regarded as asub-species of the Figure 4 embodiment.

Figures 8 and 9 illustrate a fourth species of the invention, Figure 8being a sectional elevation and Figure 9, a cross-section taken on line99 of Figure 8.

Figures 10 and 11 illustrate a fifth species of the invention, Figure 10being a sectional elevation and Figure 11, a cross-section taken on line1111 of Figure 10. The Figure 10 embodiment bears a marked resemblanceto that of Figure 8 and may therefore be properly regarded as asub-species of the Figure 8 embodiment.

In the preferred embodiment of the invention illustrated in Figures 1, 2and 3, the numeral 16 designates a generally cylindrical water tankcomposed of two identical halves 17 and 18 fitted together With avertical seam 19. While this method of construction is preferred forthis species, it will be readily appreciated that the essence of thetank 16 is a substantially cylindrical vertical wall portion 21 closedat top and bottom by the respective end wall portions 22 and 23.

In the first embodiment here under description, the tank 16 may besubstantially any cylindrical type water storage tank. It is preferred,however, to use a tank of the type disclosed in the copendingapplication of Llewellyn Evans, Serial No. 180,571, filed August 21,1950, now abandoned, wherein the tank 16 is of steel and contains acopper tank 20 immediately therewithin which c0nstitutes a linertherefor.

Tank 16 is supported by and contained within a double-walled housing 24,consisting essentially of an upright cylindrical inner wall 26 and asimilar outer wall 27, the interspace between the two walls containinginsulation 28. As best seen in Figure 3, the tank 16 is secured as bywelding to the circumferentially contiguous inner wall 26 of the housing24.

The outside flue construction is effected in the instant species byoutwardly deforming the inner wall 26 of the housing 24 to form aplurality of elongated recesses 31 spaced around and facing thecylindrical wall of the tank 16. These recesses extend at top and bottombeyond the corresponding ends of the cylindrical portion 21 of the tank16, thereby constituting, in conjunction with the cylindrical portion21, flue means for the passage of hot gases from the burner chamber 32upwardly past the tank 16 and into an upper chamber 33, formed by theend wall portion 22 and a cover plate 34 constituting the top of theheater. An axial chimney stub 36 is provided in the cover plate 34 forthe venting of the hot gases. The upper edges of the housing walls 26and 27 are secured to the cover plate 34. It is preferred to stop therecesses 31 short of the top and bottom edges of the wall 26. Thisfeature, at the bottom, serves to smoothly deflect the gases up theflues, and at the top, to deflect the gases inwardly toward the chimney36, thereby minimizing hot spots around the edge of the cover plate 34.

A water inlet pipe 37 and a Water outlet pipe 38 are provided, passingthrough the housing and tank wall into the interior of the tank 16. Atemperature sensitive element 39 is inserted into the tank to permittemperature control of the water.

The improved construction described immediately above, in which the tank16 is permitted to retain its strong and rugged cylindricalconfiguration While still obtaining the advantages of outside flueheating, makes possible the employment of a burner 41 of higher heatemission properties than could otherwise be used. Such a burner,however, brings with it the problem of abnormal heating of the interior42 of the chamber walls immediately adjacent the periphery of theburner. To allevlate excessive heating of the wall interior 42, theinstant invention contemplates that combustion air for the burner 41shall be admitted in such fashion as to continuously wipe the surface 42with a blanket of cool incoming air, thereby cooling the said surfacefrom the intense heat of the burner 41 and the immediately adjacentportion of the burner housing. To this end a horizontal annularpartition 43, spanning the interspace between the inner wall 26 and theouter wall 27 of the housing 24, is secured near the bottom of thehousing so as to provide an air inlet chamber 44 therebeneath andsupport the insulation 28 thereabove. Air is admitted to the annularchamber 44 through a plurality of inlet passages 46 provided in thebottom plate 47, which closes the bottom portion of the heater andsecures the walls 26 and 27 of the housing 24 in place.

Near the bottom of the inner wall 26, which constitutes the verticalhousing for the burner chamber 32, and below the partition 43, the wall26 is perforated to provide a plurality of air inlets 48. Within thechamber 32 and secured to the interior surface 42 is an annularhorizontal baffle 49 circumjacent the burner 41 and approximately levelwith the upper surface thereof. Combustion air is drawn in continuouslythrough the passageways 46, into the annular interspace 44, through theinlets 48, and through the annular gap between the inner edge of thebaffle 49 and the periphery of the burner 41 into the chamber 32. Thisrelatively cool air thus serves to continuously wipe the hot surfaces inthe interior of the burner housing and thus provides a blanketing layerof cool air against the heat of the burner 41.

Turning now to the species illustrated in Figure 4, the water tank isshown comprised of a vertical cylinder 51, closed at top and bottom byend plates 52 and 53, respectively, which are welded to the cylinder 51in conventional manner to constitute a water-tight tank. The wall ofcylinder 51 is deformed outwardly to form a plurality of elongate,generally vertical bosses 54, spaced around the cylinder 51. Thesebosses may be slightly inclined, as illustrated, if desired. It is to benoted that the bosses 54 do not extend the full length of the cylinder51, but stop short of the edges thereof so that securing of the endplates 52 and 53 is unaffected by the embossing. That is to say, if thecylinder 51 is circular, as is generally the case, the end plates 52 and53 may constitute simple circular caps, there being no necessity foraltering this construction to accommodate the bosses 54.

As with the first species, the Figure 4 embodiment includes adouble-walled housing 56, the inner wall 57 of which is immediatelycircumjacent the embossed portion of the cylinder 51, thereby supportingthe Water tank and forming, in conjunction with the bosses 54, fluemeans 58 for the upward passage of hot gases from the burner to thechimney. in the Figure 4 embodiment the inner cylindrical wall 57 may beformed with undisturbed cylindrical contour, since the bosses 54 of thetank provide the necessary flue means 58.

The embodiment shown in Figures 6 and 7 is similar to that shown inFigures 4 and 5, except for the readily evident difference in the shapeof the lands 54. This difference is best seen by comparison of Figuresand 7. The construction of this embodiment results in generallysemi-cylindrical flue passages 58 formed between the cylinder 51' andthe inner wall 57 of the housing 56'.

The species illustrated in Figures 8 and 9 is characterized by the factthat the cylindrical portion 61 of the water tank is deformed inwardlyto form the elongate, generally vertical channels 62 spaced around thetank. Like the Figure 4 species, that of Figure 8 is closed by top andbottom end plates 63 and 64 to form the water tank. Since the channels62 stop short of the top and bottom edges of the cylinder 61, the endplates 63 and 64, like their counterparts 52 and 53, raged not bespecially fluted to accommodate the bosses It is necessary in thisspecies, however, to form an annular recess 66 in the inner wall 67 ofthe housing 68 at the level of the top edge 69 of the cylinder 61, andan annular recess 71 at the level of the bottom edge 72 of the cylinder61, to create a gas passage past the respective edges of the cylinder,which would otherwise block the flue passages formed by the channels 62.It will be noted, however, that this deforming or channeling does notdisturb the unbroken cylindrical contour of the outer housing wall 73;the only effect to the housing being merely a narrowing of the thicknessof the insulating interspace 74 immediately circurnjacent the recesses66 and 71. As in the other embodimfints, the interspace 74 is filledwith insulation 76.

The modification illustrated in-Figures l0 and 11 is similar to that ofFigures 8 and 9 except that the inwardly deformed portions 81 aresomewhat serpentine in character, thereby providing greater passagedistance for the flue gases and causing them to remain in contafct withthe tank wall 82 for a somewhat longer period 0 time.

From the foregoing description it will be readily appreciated that theinstant improvement in water heaters of the external flue type greatlysimplifies the construction of the water tank and renders it much easierto obtain well sealed end plates at top and bottom of the tank. Ifdesired, the type of rounded-end cylinder illustrated in Figure 1 may beemployed. Either type obviates the requirement for specially fluted endplates with the attendant disadvantages and weakness of weld to thecylindrical tank wall.

It will be further appreciated that the enlarged burner made possible bythis simplification in water tank construction may be now readilyaccommodated through the use of the special air inlet means which servesto wipe the hot portion of the burner chamber walls with a stratum ofcool incoming air.

While we have herein shown and described our invention in what we haveconceived to be the most practical and preferred embodiment, it isrecognized that departures may be made therefrom within the scope of ourinvention, which is not to be limited to the details disclosed herein,but is to be accorded the full scope of the claims so as to embrace anyand all equivalent devices.

Having described our invention, what We claim as new and desire tosecure by Letters Patent is:

1. A water heater comprising in combination a substantially cylindricalwater tank closed at top and bottom by substantially hemisphericalwalls, a housing enclosing said tank and having a generally cylindricalinner wall circumferentially contiguous to said tank, said inner wall ofsaid housing being deformed outwardly to form a channel for the passageof flue gases extending upwardly the full height of said tank, saidhousing having an open space above said tank communicating with saidchannel, said housing including a cover plate having a flue opening inthe center thereof for evacuation of flue gases, and a burner centrallylocated in the bottom portion of said housing directly beneath saidtank, gases from said burner rising directly upward to the hemisphericalbottom of said tank and being deflected smoothly outward into saidchannel, thence rising in said channel to said space and out said flueopening.

2. A water heater comprising in combination a substantially cylindricalwater tank closed at top and bottom by substantially hemisphericalwalls, a substantially cylindrical housing enclosing said tank andhaving a generally cylindrical inner wall circumferentially contiguousto said tank, said inner wall of said housing being deformed outwardlyto form a channel for the passage of flue gases extending upwardly thefull height of said tank, the area of said inner wall in contact withsaid tank being appreciably greater than the area of said inner wallwhich is deformed outwardly to form said channel, whereby the heattransferring wiping action of flue gases in the channel is limited bythe wiping area available on the tank, said housing having an open spaceabove said tank communicating with said channel, said housing includinga cover plate having a flue opening in the center thereof for evacuationof flue gases, and a burner centrally located in the bottom portion ofsaid housing directly beneath said tank, gases from said burner risingdirectly upward to the hemispherical bottom of said tank and beingdeflected smoothly outward into said channel, thence rising in saidchannel to said space and out said flue opening.

References Cited in the file of this patent UNITED STATES PATENTS 62,308Barden Feb. 26, 1867 1,583,680 Fowles May 4, 1926 1,691,334 Braden Nov.13, 1928 1,752,536 Mitchell Apr. 1, 1930 1,776,984 Sinton et al. Sept.30, 1930 (Other references on following page) Schnepp Apr. 28, 1931 LumJuly 30, 1935 Strong Oct. 13, 1936 5 Breese Jan. 22, 1946 Breese Mar.19, 1946 6 Miller July 30, 1946 Kittrell Nov. 9, 1948 Jensen Dec. 28,1948 Mustee Dec. 20, 1949 Anderson et a1 Jan. 16, 1951

